INFLUÊNCIA DO EXTRATO PIROLENHOSO NA GERMINAÇÃO E CRESCIMENTO INICIAL DE HÍBRIDOS DE GIRASSOL

Abstract

Sunflower, an annual species native to North America, stands out for its adaptability, vigor, and high productive capacity even under water stress conditions. The crop has expanded in Brazil and worldwide due to its production efficiency. In the context of climate change, bioinputs such as pyroligneous extract, a byproduct of wood pyrolysis rich in organic compounds, have gained importance. Pyroligneous extract acts as a soil conditioner, plant biostimulant, and rooting inducer, contributing to improvements in the physical, chemical, and biological properties of the soil, in addition to reducing the use of agrochemicals. The objective of this study was to evaluate the influence of pyroligneous extract on the germination and early development of sunflower hybrids. The experiment was conducted at the Instituto Federal Goiano, Urutaí Campus, in two stages: laboratory and greenhouse. In the laboratory phase, the hybrid H260 was evaluated under concentrations of 1.0, 2.5, 5.0, and 10% (v v⁻¹) of pyroligneous extract, in addition to a control treatment, using a completely randomized design with six replications. Variables related to germination and early growth were analyzed, including first count, final germination, shoot length, root length, total seedling length, and dry mass. In the greenhouse stage, five hybrids (H250, H251, H260, T203, and T204) were subjected to concentrations of 1 and 5 L of pyroligneous extract per 100 L of water, in addition to the control treatment. Germination, plant height, stem diameter, root length, and dry mass were evaluated. Data were subjected to analysis of variance and compared using 95% confidence intervals to determine the effects of pyroligneous extract concentrations on the initial performance of sunflower. The results indicate that pyroligneous extract has potential for use in sunflower cultivation; however, its efficiency depends on the applied concentration and the genotype evaluated. Under laboratory conditions, the 1% concentration showed performance similar to the control, with overlapping confidence intervals for some variables, indicating no significant negative effect. Higher concentrations, especially 5% and 10%, showed a phytotoxic tendency, reducing early development. In the greenhouse, the 1% dose maintained good germination and growth indices for most hybrids, whereas the 5% concentration resulted in more variable responses among the genotypes. It can be concluded that pyroligneous extract is a promising bioinput for sunflower cultivation when applied at appropriate concentrations, and 1% was the dose with the greatest application potential under the evaluated conditions.